Use of benzopyranes for preventing allograft rejection

Abstract

 A method for suppressing the rejection of allogeneic transplants in a mammal, including a human comprising administering to said mammal an effective amount of the compound of the formula

wherein n, A, B, R¹ and R² are as defined above, or the pharmaceutically acceptable salt thereof.

Description

Background of the Invention

[0001] This invention relates to the use of certain benzopyran and benzo-fused compounds and their pharmaceutically acceptable acid addition salts for the prevention of alograft rejection in mammals, including humans.

[0002] Allograft rejection, be it of a vascularized organ, skin or tissue, is characterized by a highly complex series of cellular and humoral interactions in which T lymphocytes play a central, essential role. T cells initiate and regulate graft rejection, but a mixed populaton of cells and effector mechanisms contribute to graft failure. This wide array of effector mec-anisms leading to graft destruction include alloantibody dependent mechanisms (B lymphocytes) antigen-specific cytotoxic T cells and a variety of non-specific effector cells including macrophages, natural killer (NK) cells, polymorphonuclear leukocytes (PMN, e.g., neutrophils, eosinophils), and lymphokine-activated killer (LAK) cells. The cellular pathways which mediate graft rejection are multiple and complex.

[0003] Acute cellular rejection is the result of migration of inflammatory cells into the graft. Lymphocytes recognize and react to foreign antigens, undergo proliferative expansion and initiate humoral events, i.e., antibodies, cytokines, and proinflammatory mediators; these in turn recruit/activate, non-specifically, various cells of the monocyte/macrophage lineage to infiltrate and destroy graft tissue. Also, at this point, large granular lymphocytes and PMN may be seen in the graft.

[0004] Secondarily, most grafts are subject to ischemic injury due to cold ischemia time and vasoconstriction of donor arteries following reperfusion and high dose immunosuppression immediately after transplantation. This event is characterized by infiltration of the graft by inflammatory cells, primarily, monocytes, macrophages and PMN. The donor arterial endothelial cells are most likely the primary target of transplant ischemia-reperfusion injury. This lesion is characterized by a local, chronic cellular immune response of the endothelium composed of T cells and macrophages which continue to amplify and perpetuate the immune/inflammatory response, resulting in loss of intact endothelium and function combined with chronic immunologic injury.

[0005] The incidence of transplant associated arteriosclerosis escalates with increasing survival time; lesions develop rapidly (within 3 months) and occur throughout the arterial tree of the graft. Chronic rejection leads to gradual deteriorationof graft function and is a major threat to long-term survival of transplanted organs.

Summary of the Invention

[0006] The present invention relates to a method for suppressing the rejection of allogeneic transplants in a mammal, including a human, comprising administering to said mammal an effective amount of a compound of the formula

or a pharmaceutically acceptable acid addition salt thereof wherein

n is 1,2 or 3;

A is oxygen, sulfur, CH₂, NH or N(C₁-C₆)alkyl;

B is CHR³ wherein each R³ is hydrogen, (C₆-C₁₀)aryl(C₆-C₁₀)aryl or (C₅-C₁₀)aryl(C₆-C₁₀)aryl(C₆-C₁₀)alkyl;

R¹ is tetrazolyl, carboxy, carboxy(C₂-C₆)alkenyl optionally substituted by one or two (C₁-C₆)alkyl groups; (C₁-C₆)alkyl, (C₃-C₇)cycloalkyl, (C₃-C₇)cycloalkyl(C₁-C₆)alkyl wherein the alkyl or cycloalkyl groups are optionally substituted by hydroxy, carboxy or tetrazolyl; or a group of the formula

wherein a is 0,1, 2, 3 or 4;

R⁸ and R⁹ are each independently hydrogen or (C₁-C₆)alkyl; and

R¹⁰ and R¹¹ are each independently hydrogen, hydroxy, (C₁-C₆)alkyl, perfluoro(C₁-C₆)alkyl, (C₁-C₆)alkylsulfinyl, (C₆-C₁₀)arylsulfinyl, R¹⁵sulfonyl wherein R¹⁵ is (C₁-C₆)alkyl, perfluoro(C₁-C₆)alkyl, (C₃-C₈)cycloalkyl, (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl; or (C₆-C₁₀)aryl wherein each aryl or heteroaryl substituent is optionally substituted by one or two groups selected from fluoro, chloro, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl and (C₆-C₁₀)arylsulfonyl;

or a group of the formula

wherein b is 0, 1, 2 or 3;

c is 0 or 1;

Y is oxygen, sulfur, CH₂, NH or N(C₁-C₆)alkyl; and

Z is (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl wherein the aryl or heteroaryl substituents are optionally substituted by one to three groups selected from fluoro, chloro, (C₁-C₆)alkyl optionally substituted by hydroxy; R¹²SO₂NH wherein R¹² is (C₁-C₆)alkyl or perfluoro(C₁-C₆)alkyl; R¹³SO₂NHCO wherein R¹³ is (C₁-C₆)alkyl, (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl wherein aryl or heteroaryl substituents are optionally substituted by R¹⁴, (C₆-C₁₀)aryl or R¹⁴(C₆-C₁₀)aryl wherein R¹⁴ is as defined above; (R¹⁵SO₂)NH, (R¹⁵CO)NH, (R¹⁵CO₂)NH wherein R¹⁵ is as defined above; (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl, carboxy, tetrazolyl or the group of formula II wherein a, R⁸, R⁹, R¹⁰ and R¹¹ are as defined above; and

R² is hydrogen, fluoro, chloro, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₆-C₁₀)arylsulfinyl, (C₁-C₆)alkylsulfonyl or (C₆-C₁₀)arylsulfonyl.

[0007] The term "alkyl", as used herein, unless otherwise indicated, includes saturated monovalent hydrocarbon radicals having straight, branched or cyclic moieties or combinations thereof.

[0008] The term "alkoxy", as used herein, includes O-alkyl groups wherein "alkyl" is defined above.

[0009] The term "aryl", as used herein, unless otherwise indicated, includes an organic radical derived from an aromatic hydrocarbon by removal of one hydrogen, such as phenyl or naphthyl, optionally substituted by 1 to 3 substituents independently selected from the group consisting of fluoro, chloro, cyano, nitro, trifluoromethyl, (C₁-C₆)alkoxy, (C₆-C₁₀)aryloxy, trifluoromethoxy, difluoromethoxy and (C₁-C₆)alkyl.

[0010] The term "heteroaryl", as used herein, unless otherwise indicated, includes an organic radical derived from an aromatic heterocyclic compound by removal of one hydrogen, such as pyridyl, furyl, pyroyl, thienyl, isothiazolyl, imidazolyl, benzimidazolyl, tetrazolyl, pyrazinyl, pyrimidyl, quinolyl, isoquinolyl, benzofuryl, isobenzofuryl, benzothienyl, pyrazolyl, indolyl, isoindolyl, purinyl, carbazolyl, isoxazolyl, thiazolyl, oxazolyl, benzthiazolyl or benzoxazolyl, optionally substituted by 1 to 2 substituents independently selected from the group consisting of fluoro, chloro, trifluoromethyl, (C₁-C₆)alkoxy, (C₆-C₁₀)aryloxy, trifluoromethoxy, difluoromethoxy and (C₁-C₆)alkyl.

[0011] Compound P is defined as (+)-2-[3,4-dihydro(3S,4R)-4-hydroxy-3-(4-phenyl-phenylmethyl)-7- 2H, 1-benzopyran)]cyclopentane carboxylic acid.

[0012] The positions on the ring of formula I, when n is 2, as used herein, are defined as follows:

The compound of formula I may have chiral centers and therefore exist in different enantiomeric forms. This invention relates to all optical isomers and stereoisomers of the compounds of formula I and mixtures thereof.

[0013] A preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein n is 2.

[0014] Another preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein A is oxygen.

[0015] Another preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein n is 2 and B is in the 3-position.

[0016] Another preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein R² is hydrogen or fluoro.

[0017] Another preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein n is 2 and R¹, in the 7-position, is 2-carboxyphenyl, 2-carboxy-5-chlorophenyl, 2-carboxy-4-chlorophenyl, 2-carboxy-3-fluorophenyl, 2-carboxy-5-fluorophenyl, 2-carboxy-5-chlorophenyl, 2-carboxy-5-trifluoromethylphenyl, 2-trifluoromethylsulfonylamine-5-fluorophenyl, 2-carboxy-4.fluorophenyl, 2-carboxy-5-fluorophenyl, 2-tetrazoyl-5-fluorophenyl or 3-carboxyphenyl.

[0018] Another preferred embodiment of this invention relates to the above method wherein the compound administered is one wherein n is 2; A is oxygen; B is in the 3-position; R² is hydrogen or fluoro; and R¹, in the 7-position, is 2-carboxyphenyl, 2-carboxy-5-chlorophenyl, 2-carboxy-4-chlorophenyl, 2-carboxy-3-fluorophenyl, 2-carboxy-5-fluorophenyl, 2-carboxy-5-trifuoromethylphenyl, 2-trifluoromethylsulfonylamine-5-fluorophenyl, 2-carboxy-4-fluorophenyl, 2-carboxy-5-fluorophenyl, 2-tetrazoyl-5-fluorophenyl or 3-carboxyphenyl.

Detailed Description of the Invention

[0019] The benzopyran and benzo-fused compounds of formula I can be prepared by one or more of the synthetic methods described and referred to in United States Patent 5,552,435 and PCT international application number PCT/IB95/00397. United States Patent 5,552,435 and PCT international application number PCT/IB95,00397 are incorporated herein by reference in their entirety.

[0020] The compounds of the invention can be administered to humans by various routes including orally. parenterally and topically, and through the use of suppositories and enemas. On oral administration, dosage levels of about 0.5 to 1000 mg/day, advantageously about 5-500 mg/day may be given in a single dose or up to three divided doses. For intravenous administration dosage levels are about 0.1-500 mg/day, advantageously about 1.0-100 mg/day Intravenous administration can incluce a continuous drip. Variations will necessarily occur depending on the age, weight and cordition of the subject being treated and the particular route of administration chosen as will be known to those skilled in the art.

[0021] The compounds of the invention may be administered alone, but will generally be administered in admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they can be administered orally in the form of tablets containing such excipients as starch or lactose, or in capsules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavoring or coloring agents. They can be injected parenterally, for example, intramuscularly, intravenously or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which can contain other solutes, for example, enough salt or glucose to make the solution isotonic.

In Vivo Murine Cardiac Ear Pinnae Model of Transplatation

[0022] Methods: A rapid, facile 2-week murine bioassay of non-vascularized cardiac tissue transplantation,t he murine cardiac ear pinna model of acute allograft rejection, was used to evaluate the dose-response relationship of immunosuppressive drugs on allograft rejection. In this model, donor BALB/C (H2^d) neonatal hearts are transplanted into recipient C3H/HeN (H2^k) ear pinna pouches without vacular anastomoses. Survivinghearts are revascularized and usually resume beating on day 3 to 6. Untreated allografts failed prior to day 12 (MST = 10.5 + 0.9d, n=13). Isografts survived indefinitely. All compounds are given on day 0 to 17 COMPOUND P [(+)-2-[3,4-dihydro(3S,4R)-4-hydroxy-3-(4-phenyl-phenylmethyl)-7-(2H,1-benzopyran)]cyclopentane carboxylic acid] was given orally in 0.5% Methylcellulose. Grafts were assessed by visual examination for contraction on alternate days (from 6 to 18) and graft survival was defined as the post-transplant day on which contractions cease. Efficacy data from day 6 to 18 is presented as mean survival days (+SD) and was analyzed by Log Rank Analysis. Graft survival values were determined at day 18. Any graft surviving at day 18 was censored for statistical purposes.

[0023] Results: In these studies, the efficacy of COMPOUND P was evaluated as graft survival on day 18 dosed in monotherapy. The efficacy of COMPOUND P, as a single agent, in acute rejection was significant (p<0.01) at highest dose, 300 mg/kg d: but not at the lower doses tested (200, 100, and 30 mg/kg).

Table 1.

Effect of Monotherapy on Graft Survival
Treatment	Mean ± Std Dev	Log Rank p value (vs No Rx)	n
COMPOUND P (30 mg/kg/d)	11.0 ± 1.1	0.2534	6
COMPOUND P (100 mg/kg/d)	10.3 ± 0.7	0.5586	8
COMPOUND P (200 mg/kg/d)	10.3 ± 0.7	0.5586	8
COMPOUND P (300 mg/kg/d)	11.8 ± 1.1	0.0045	1 1
No Treatment	10.5 ± 0.9	NA	1 3

[0024] The present invention is illustrated by the following examples, but it is not limited to the details thereof.

Example 1

A. 2',4'-Dihydroxy-3-chloropropiophenone

[0025] To a stirred mixture of resorcinol (200 g, 1.82 mol) and 3-chloropropionic acid (200 g, 1.84 mol) was added trifluoromethane sulfonic acid (1 kg) in one portion. The solution was heated slowly over 45 minutes to 80°C then cooled to room temperature over 15 minutes and poured into chloroform (4.0 L). The organic portion was slowly poured into water (4.0 L) and the layers separated. The aqueous layer was extracted with chloroform (2 x 2.0 L). The combined organic layers were washed with brine, dried over sodium sulfate and filtered. Concentration in vacuo gave an orange semi-solid (244.1 g) which was used crude in the next step.

[0026] ¹H-NMR (300 MHz, CDC1₃): 12.56 (1H, s), 7.63 (1H, d, J=7.6Hz), 6.37-6.46 (2H, m), 3.92 (2H, t, J=6.3Hz), 3.41 (2H, t, J=6.3Hz).

B. 7-Hydroxybenzopyran-4-one

[0027] To a cooled (5°C) solution of 2N sodium hydroxide (10.0 L) was added the compound of step A (244.1 g) in one portion. The solution was warmed to room temperature over 2 hours using a warm water bath then recooled to 5°C and the pH adjusted to 2 with 6 M sulfuric acid (1.2 L). The mixture was extracted with 3 x 3.0 L of ethyl acetate, washed with brine (1 x 2.0 L) dried over sodium sulfate and filtered. Concentration in vacuo gave a tan solid. Trituration with hexanes, and filtration afforded 173.7 g (58% yield) of the title compound. M.P. 136°C-137°C.

C. 7-[(Trifluoromethylsulfonyl)oxy]-benzopyran-4-one

[0028] To a stirred solution of the compound of step B (173.7 g, 1.05 mole) in methylene chloride (3.0 L) at - 78°C was added triethylamine (320 g, 3.16 mole) and dimethylaminopyridine (2.5 g). After total dissolution, trifluoromethane sulfonic anhydride (327 g, 1.16 mole) was added dropwise over 20 minutes, the material was stirred for 30 minutes at -78°C, and then warmed to room temperature over 2 hours. The reaction mixture was poured into saturated ammonium chloride solution (2.5 L) and the layers separated. The aqueous layer was extracted with 2 x 2.0 L of methylene chloride The combined organic fractions were washed with water (1 x 1.0 L), dried over magnesium sulfate and iltered. Concentration in vacuo gave a red oil. Chromatography over silica gel (1 kg) eluting with (8:1) hexane: ethyl acetate gave after solvent removal 211.1 g. (69% yield) of the title product. M P. 43-44 °C.

D. 7-[(Trifluoromethylsulfonyl)oxy]-3-phenylmethyl-benzopyran-4-one

[0029] To a stirred solution of the product of Step C (27 g, 91.2 mmole) in 183 mL of methanol was added benzaldehyde (11.1 mL, 109 mmole) followed by pyrrolidine (9.1 mL, 109 mmole). The mixture was stirred at room temperature ovemight, cooled to 0°C and filtered. The solid was washed once with 50 mL of ice-cold methanol and then dried in vacuo; 35.2 g, (75% yield) of the title product was recovered. M.P. 133-135°C.

[0030] ¹H NMR (300 MHz, CDCl₃): 8.11 (1H, d, J=8.7Hz), 7.91 (1H, bs), 7.40-7.51 (2H, m), 7.24-7.38 (3H, m), 6.97 (1H, dd, J=8.7Hz, 2.4Hz). 6.91 (1H, d, J=2.4Hz), 5.40 (1H, bs).

E. 7-[(Trifluoromethylsulfonyl)oxy]-3-phenylmethyl-benzopyran-4-one

[0031] To a solution of the compound of step D (26.6 g, 69.2 mmole) in 250 mL of ethyl acetate in a 500 mL Parr shaker flask was added 10% palladium on carbon catalyst (1.3 g). The mixture was hydrogenated at 40 psi until hydrogen uptake ceased after about 3 hours. The mixture was filtered through celite (a tradename for diatamaceous earth) to remove the palladium catalyst, and chromatographed over silica gel (hexane-ether); 25.1 g (94% yield) of the title product was obtained. M.P. 56-58°C.

[0032] ¹H NMR (300 MHz. CDCl₃): 8.01 (1H, d. J=8.5Hz), 7.20-7.35 (5H, m), 6.981-6.96 (2H, m), 4.42 (1H, dd, J=11.6, 4.4Hz), 4.22 (1H, dd, J=11.6Hz, 8.7Hz), 3.26 (1H, dd, J=14.0, 4.4Hz), 2.90-3.05 (1H, m), 2.70(1H, dd, J=14.0. 8.7Hz).

F. 7-(Trimethylstannyl)-3-phenylmethyl-benzopyran-4-one

[0033] To a stirred solution the compound of step E (9.20 g, 25.0 mmole) in 200 mL of dioxane was added lithium chloride (3.20, 75.0 mmole), Pd(PPh₃)₄ (1.15 g, 1.0 mmole), 3 crystals of butylated hydroxytoluene, and hexamethylditin (9.0 g, 27.5 mmole). The mixture was heated to reflux for 1.5 hours, cooled to room temperature and poured into 150 mL of saturated, aqueous ammonium chloride solution. The mixture was extracted with 3x150 mL of diethylether and the combined organic fractions were washed with brine, dried over sodium sulfate and filtered. Evaporation in vacuo gave a yellow semi solid which was chromatographed over silica gel (5:1 hexane: ether) to give 8.90 g (89% yield) of the title product. M.P. 84-86°C.

[0034] ¹H NMR (300 MHz,CDCl₃): 7.85 (1H, d, J=8.7Hz), 7.18-7.37 (5H, m), 7.14 (1H, d, J=8.7Hz), 7.11 (1H, s), 4.38 (1H, dd, J=11.6, 4.5Hz), 4.17 (1H. dd, J=11.6Hz, 8.4Hz), 3.28 (1H, dd. J=14.0, 4.4Hz), 2.84-2.95 (1H, m), 2.71 (1H, dd, J=14Hz, J=11.OHz). 0.31 (9H, s).

G. 7-(3-Carbonethoxyphenyl)-3-phenylmethyl-benzopyran-4-one

[0035] To a stirred solution of the compound of step F (7.0 g, 17.5 mmole) in dimethylformamide (DMF) (35 mL) was added Pd(PPh₃)₂C1₂ (490 mg, 0.7 mmole), 3 crystals of BHT and methyl-3-iodobenzoate (5.0 g, 19.1 mmole). The mixture was stirred at reflux for 1.5 hours, cooled to room temperature and poured into 150 mL of saturated aqueous ammonium chloride solution The mixture was extracted with 3x150 mL of diethyl ether, and the combined extract was washed with 2x100 mL of water, and then brine. The solution was dried over sodium sulfate, filtered and evaporated in vacuo to afford a yellow oil. Chromatography over silica gel (4:1 hexane: ether elution) afforded 6.51 g of the title compound as a viscous oil.

[0036] ¹H NMR (300 MHz, CDC1₃): 8.29 (1H, t, J=1.6Hz), 8.06 (1H, dd, J=7.6. 1.6Hz), 8.00 (1H, d, J=8.2Hz), 7.79 (1H, dd, J=7.6Hz, 1.6Hz), 7.53 (1H, t, J=7.6Hz). 7.22-7.36 (7H, m), 4.41 (1H, dd, J=11.6, 4.5Hz), 4,21 (1H, dd, J=11.6, 8.5Hz), 3.94 (3H, s), 3.31 (1H, dd, J=14.0, 4.4hz), 2.91-2.99 (1H, m), 2.73 (1H, dd, J=14.0, 11.1Hz)

H. 7-(3-Carbomethoxyphenyl)-4-hydroxy-3-phenylmethyl-benzopyran

[0037] To a stirred solution of the compound of step G (6.50 g, 17.5 mmole) in 35 mL of methanol at room temperature was added sodium borohydride (940 mg, 26.0 mmole) in one portion. The dark mixture was stirred at room temperature for 2 hours then poured into saturated aqueous ammonium chloride solution (75 mL) and extracted with 3x75 mL of diethyl ether. The combined extracts were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to give an off-yellow oil. Chromatography on silica gel eluting with 4:1 hexane: ether afforded first 3.26 g of the cis ring isomer of the title compound, and then 1.98 g of the trans isomer of the title compound as viscous oils, total yield 81%.

[0038] C is ring isomer: ¹H NMR (300 MHz, CDCl₃): 8.26 (1H, t, J=1.7Hz), 8.02 (1H, dt, J=7.8, 1.7Hz), 7.76 (1H, dt, J=7.8, 1.7Hz), 7.50 (H, t, J=7.8Hz), 7.41 (1H, d, J=7.9Hz), 7.31 (1H, d, 7.3Hz), 7.14-7.25 (6H, m), 4.58 (1H, t, J=7.2Hz), 4.28 (1H, dd, J=9.1, 2.5Hz), 4.03 (1H, dd, J=9.1, 5.4Hz), 3.93 (3H, s), 2.78 (1H), 2.77 (1H, dd, J=13.7, 6.2Hz), 2.58 (1H, dd, J=13.7, 9.1 Hz), 2.20-2.29 (1H, m), 1.83 (1H, d, J=7.2Hz).

[0039] Trans ring isomer ¹H NMR (300 MHz, CDC1₃): 8.23 (1H, t, J=1.7Hz). 7.98 (1H, dt, J=7.8Hz), 7.74 (1H, t, J=7.8Hz, 1.7Hz), 7.48 (1H, t, J=7.8Hz), 7.20-7.36 (6H, m), 7.15 (1H, dd, J=8.0. 1.8Hz), 7.09 (1H, d, J=1.8Hz), 4.56 (1H, dt, J=4.7, 3.8Hz), 4.12-4.19 (2H, m), 3.92 (3H, s), 2.90 (1H, dd, J=13.6, 8.4.Hz), 2.70 (1H, dd, J=13.6, 7.2Hz), 2.36-2.39 (1H, m), 1.75 (1H, d, J=4.7Hz).

J. N-a-t-Butoxycarbonyl-L-tryptophan-7(3-carbomethoxyphenyl)-3-phenylmethyl-chroman-4-yl]-ester

[0040] To a stirred solution of the compound of step H (2.5 g, 6.7 mmole) in 70 ml of CH₂Cl₂ was added DMAP (897 mg., 7.34 mmole, 1.1 eq.), DCC (1.51 g, 7.34 mmole, 1.1 eq ) and N-t-Boc-L-tryptophan (2.4 g. 8.01 mmole, 1.2 eq.). The mixture was stirred at room temperature for 12 hours, filtered and washed with IM HCI and brine. The organic layer was dried over MgSO₄, filtered and concentrated in vacuo. Chromatography (silica gel-3:1 cyclohexane:ether) afforded 860 mg of the less polar diastereomer (Rf=0.3) and 700 mg of the more polar moving diastereomer (Rf=0.2). The less polar product (3S, 4R): ¹H-NMR (300 MHz, CDCI3); 8.29 (1H, s), 8.03 (2H, d, J=7.8 Hz), 7.77-7.83 (2H, m), 7.52 (2H, t, J=7.6 Hz), 7.02-7.33 (5H, m), 6.64 (1H, s), 5.65 (1H, s), 5.06 (IH, d, J=8.4 Hz), 4.58-4.62 (1H, m), 3.95 (3H, s), 3.73-3.85 (2H, m), 3.18-3.28 (2H, m), 2.45-2.61 (2H, m), 2.09-2.15 (1H, brd s), 1.39 (9H, s). The more polar product (3R,4S); ¹H-NMR (300 MHz, CDCl₃): 8.25 (1H, s), 8.01 (1H, d, J=7.8 Hz), 7.94 (1H, brd s), 7.74 (1H, d, J=8.2 Hz), 7.54 (1H, d, J=11.9 Hz), 7.48 (1H, t, J=7.8 Hz), 7.09-7.38 (H, m), 6.95 (1H, s), 5.61 (1H, s), 5.08 (1H, d, J=8.2 Hz), 4.55-4.60 (1H, m), 3.94 (3H, s), 3.73-3.76 (2H, m), 3.22-3.35 (2H, m), 2.42-2.60 (2H, m), 1.90-1.96 (1H, m), 1.39 (9H, s).

K. 3S,4R-7-(3-carboxyphenyl)-4-hydroxy-3-phenylmethyl-2 H-1-benzopyran

[0041] To a stirred solution of the less polar 4R,3S tryptophan ester of step L (840 mg, 1.08 mmole) in 10 mL of methanol was added 10 mL of 2M NaOH solution. The mixture was refluxed for 8 hours, cooled and acidified to a pH of 4 with 1M HCI. The cloudy emulsion was extracted with 3x20 mL of ethyl acetate, and the combined organic fractions were washed with brine and dried over MgSO₄. Filtration and solvent removal in vacuo afforded a yellow foam. Chromatography (silica gel-ethyl acetate: hexane: acetic acid -35:75:1) afforded 210 mg of product. ¹H NMR. (300 MHz, CD₃CN): 8.22 (1H, t, 1.7Hz), 7.97 (1H, dt, J=7.8, 1.7Hz), 7.87 (1H, dt. J=7.8, 1.7Hz), 7.55 (1H, t, J=7.8Hz), 7.42 (1H, d, J=7.9Hz), 7.15-7.36 (6H, m), 7.10 (1H, d. J=1.8Hz), 4.44 (1H, d, J=4.9Hz), 4.19 (1H, dd, J=9.1, 2.5Hz), 3.97 (1H, dd, J=9.1, 5.4Hz), 2.72 (1H, dd, J=13.7, 6.2Hz), 2.51 (1H, dd, J=13.7, 9.1Hz), 2.04-2.20 (3H, m). [a]_D=+11.1 at C=1.00 in methanol. M.P.=210-212°C.

[0042] Saponification as above of the more polar 3R,4S tryptophan-ester (700 mg) gave the 3R,4S enantiomer,¹H-NMR (300 MHz, CD₃CN): 8.22 (1H, t, 1.7Hz), 7.97 (1H, dt, J=7.8, 1.7Hz), 7.87 (1H, dt, J=7.8, 1.7Hz), 7.55 (1H, t, J=7.8Hz), 7.42 (1H, d, J=7.9Hz), 7.15-7.36 (6H, m), 7.10 (1H, d. J=1.8Hz), 4.44 (1H, d, J=4.9Hz), 4.19 (1H, dd, J=9.1, 2.5Hz), 3.97 (1H, dd, J=9.1, 5.4Hz), 2.72 (1H, dd, J=13.7, 6.2Hz), 2.51 (1H, dd, J=13.7, 9.1 Hz), 2.04-2.20 (3H, m). [a]_D=-11.0 at c=1.01 in methanol. MP=209-211°C.

L. Trans 3-phenylmethyl-4-hydroxy-7-(3-carboxyphenyl)-2H-1 -benzopyran

[0043] Saponification as in step K of the trans ring isomer of step H gave the corresponding acid. ¹H NMR (300 MHz, CD₃CN): 8.22 (1H, t, 1.7Hz), 7.97 (1H, dt, J=7.8, 1.7Hz), 7.87 (1H, dt, J=7.8, 1.7Hz), 7.55 (1H, t. J=7.8Hz), 7.42 (1H, d, J=7.9Hz) 7.15-7.36 (6H, m), 7.10 (1H, d, J=1.8Hz), 4.44 (1H, d. J=4 9Hz), 4.19 (1H, dd. J=9.1, 2.5Hz). 3.97 (1H. dd, J=9.1, 5.4Hz), 2.72 (1H, dd, J=13.7, 6.2Hz), 2.51 (1H, dd, J=13.7, 9.1 Hz), 2.04-2.20 (3H, m). M.P. 210-212°C.

Example 2

[0044] The following compounds in Table 1 were prepared by saponification in accordance with Example 1J. The melting points are in degrees Celsius.

Example 3

[0045] By saponification of the corresponding ester in accordance with Example 1J, 7-(4-hydroxy-3-carboxyphenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran was formed having a melting point of 158-160°C (cis) and 173-175°C (trans).

Example 4

A. 7-[(5-fluoro-(2-(4,4-dimethyl-2-oxazolinyl)phenyl]-3-phenylmethylene-1-benzopyran-4-one

[0046] To a stirred solution of 2-(4-fluorophenyl)-4,4-dimethyl-2- oxazoline (1.0 eq in tetrahydrofuran, .5M concentration) at -78°C under N₂ was added n-butyllithium in hexanes (1.1 eq., 2.5M solution). The mixture was stirred at -78°C for 1 hour, then ZnCl₂ (1 M solution in ether, 1.1 eq.) was added. The mixture was warmed to 10°C over 1 hour to give 2-(4-flucrophenyl-2-chlorozinc)-4,4-diethyl-2-oxazoline (not isolated). To this solution was added 7-[((trifluoromethyl)sulfonyl)oxy]-3-phenylmethylene-1-benzopyran-4-one (1.0 eq.) and Pd (PPh₃)₄ (.02 eq.). The mixture was refluxed (68°C) for 3 hours, cooled to room temperature and poured into NH₄CI solution. The solution was extracted with 3 times diethyl ether and the combined organic fraction dried over MgSO₄. Filtration followed by solvent removal in vacuo and column chromatography (silica gel - 2:1 hexane:ether) gave the title compound as a yellow solid, 65% yield, m.p. 110-112°C. ¹H-NMR (300 MHz, CDCI₃): 8.04 (1H, d), 7.91 (1H, s), 7 78 (1H, dd), 7.41-7.52 (3H. m), 7.31 (2H, d), 7.06-718 (3H, m). 7.02 (1H, s), 5.40 (2H, s), 3.86 2H, s), 1.31 (6H, s)

B. (3S*,4R*)7-[5-fluoro-(2-(4,4-dimethyl-2-oxazolinyl)phenyl]-4-hydrox. -3-phenylmethyl-2H-1-benzopyran

[0047] To a stirred solution of the compound from step A in THF (.1M) at 0°C was added LiAlH₄ (1M in ether, 2.2 eq) dropwise over 10 minutes. The mixture was warmed to room temperature and stirred for 12 hours. The mixture was cooled to 0°C, quenched with Rochelles salt, and filtered through diatomaceous earth. The aqueous layer was extracted twice with ethylacetate, and the combined organic layers were washed with brine and dried over MgSO₄. Filtration an solvent removal afforded a yellow oil. Chromatography over silica gel (ethylacetate:hexane) afforded a 60% yield of a white solid. M.P. 65-70°C (decomposed). Anal. calcd. for C₂₇H₂₆NO₃F: C, 75.15; H, 6.07; N, 3.25. Found: C. 74.75, H, 6.02. N, 3.09. ¹H-NMR (300 MHz, CDCI₃) :7.70 (1H, dd), 7.02-7.37 (8 H, m), 6.96 (1H, dd), 7.91 (1H, d), 4.51 (1H, d),4 23(1H, dd), 4.39 (1H, dd) 3.87 (2 H, dd), 2.74 (1H, dd), 2.55 (1H, dd), 2.18-2.28 (1H, m) 1.31 (6 H. d).

C. (3S*,4R*)7-(2-carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0048] The compound from step B is dissolved in methyl iodide (0.5M) at room temperature and stirred for 24 hours. The methyl iodide was removed in vacuo, the oily solid was dissolved in CH₂Cl₂ and the solvent removed in vacuo. This operation was repeated to remove traces of methyl iodide. The solid was dissolved in methanol (0.5M) and 2M NaOH (.5M) was added. The mixture was refluxed for 5 hours, cooled to room temperature and acidified to pH 2 with 1 M HCI. The mixture was extracted twice with ethyl acetate, washed with brine, and dried over MgSO₄. Filtration and solvent removal in vacuo, followed by chromatography (silica gel, 10:1 methylene chloride:methanol) gave the desired acid, 93% yield. ¹H-NMR (300 MHz, CD₃COCD₃): 7.80 (1H, dd), 7.48 (1H, d), 7.18 (7H, m), 7.13 (1H, dd), 6.91 (1H, dd), 6.80 (1H, d), 4.52 (1H, d), 4.23 (1H, dd), 3.96 (1H, dd), 2.89 (1H, dd), 2.54 (1H, dd), 2.19-2.30 (1H, m).

D1. (3S,4R)-7-(2-carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0049] The compound from step C is dissolved in diethyl ether (0.1M) and warmed to reflux. To the solution was added dropwise S(-)methylbenzylamine (1 eq) in diethyl ether (0.1M), dropwise over 10 minutes. The mixture was cooled to room temperature and stirred for 48 hours. The precipitated salt was filtered then restirred 2 times at reflux in diethyl ether (0.1M) for 24 hours, followed by filtration. The salt (M.P.=170-173°C) was taken up in methylene chloride and washed 3 times with 1M HCI, then once with brine, dried over MgSO₄, and filtered. Solvent removal in vacuo and recrystallization (1:1-hexane:ether) gave white fine crystals, more than 99.8% enantiomeric excess by HPLC analysis. [a]_D²⁵=+23.8, c=0.6 in CHCI₃. M.P. = 119-121°C. Anal. Calcd for C₂₃H₁₉O₄F: c, 73.01; H, 5.06. Found: C, 72.88: H, 4.76.

D2. (3R,4S)7-(2-carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0050] The filtrate from the combined salt slurries in step D1 was washed three times with 1M HCl, once with brine. and dried over MgSO₄. Filtration and solvent removal gave a yellow solid. A similar procedure as described in step D1 using R (+) methylbenzyl amine afforded the desired product. [a]_D²⁵=-23.4 (c=0.6 in CHCl₃), M.P.=118-120°C. Anal. Calcd. for C₂₃H₁₉O₄F: C, 73.01; H, 5.06. Found: C, 73.03; H, 4.84.

Example 5

(3S,4R)-7-(2-Trifluoromethanesulfonylamine-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

A. 2',4'-Dihydroxy-3-chloropropiophenone

[0051] To a stirred mixture of resorcinol (200 g, 1.82 mol) and 3-chloropropionic acid (200 g, 1.84 mol) was added trifluoromethane sulfonic acid (1 kg) in one portion. The solution was heated slowly over about 45 minutes at about 80°C then cooled to room temperature over about 15 minutes and poured into chloroform (4.0 L). The organic portion was slowly poured into water (4.0 L) and the layers separated. The aqueous layer was extracted with chloroform (2 x 2.0 L). The combined organic layers were washed with brine, dried over sodium sulfate and filtered. Concentration in vacuo gave an orange semi-solid (244.1 g) which was used crude in the next step. ¹H-NMR (300 MHz, CDCl₃): 12.56 (1H, s), 7.63 (1H, d, J=7.6Hz), 6.37-6.46 (2H, m), 3.92 (2H, t, J=6.3Hz), 3.41 (2H, t, J=6.3Hz).

B. 7-Hydroxybenzopyran-4-one

[0052] To a cooled (about 5°C) solution of 2N sodium hydroxide (10.0 L) was added the compound of Example 1A (244.1 g) in one portion. The solution was warmed to room temperature over about 2 hours using a warm water bath then recooled to about 5°C and the pH adjusted to 2 with 6 M sulfuric acid (1.2 L). The mixture was extracted with 3 x 3.0 L of ethyl acetate, washed with brine (1 x 2.0 L) dned over sodium sulfate and filtered. Concentration in vacuo gave a tan solid. Trituration with hexanes. and filtration afforded 173.7 g (58% yield) of the title compound of this Example 1B, M P. 136°C-137°C.

C. 7-[Trifluoromethylsulfonyloxy]-benzopyran-4-one

[0053] To a stirred solution of the compound of Example 1B (173.7 g, 1.05 mole) in methylene chloride (3.0 L) at about -78°C was added triethylamine (320 g, 3.16 mole) and dimethylaminopyridine (2 5 g). After total dissolution trifluoromethane sulfonic anhydride (327 g 1.16 mole) was added dropwise over about 20 minutes, the material was stirred fcr about 30 minutes at about -78°C, and then warmec to room temperature over about 2 hours. The reaction mixture was poured into saturated ammonium chloride solution (2.5 L) and the layers separated The aqueous layer was extracted with 2 x 2.0 L of methylene chloride. The combined organic fractions were washed with water (1 x 1.0 L), dried over magnesium sulfate and filtered. Concentration in vacuo gave a red oil. Chromatography over silica gel (1 kg) eluting with (8.1) hexane:ethyl acetate gave, after solvent removal, 211.1 g. (69% yield) of the title product. M P. 43-44°C.

D. 7-[(trifluoromethylsulfonyl)oxy]-3-phenyl-methylene-benzopyran-4-one

[0054] To a stirred solution of the product of Example 1C (27 g, 91.2 mmole) in 183 mL of methanol was added benzaldehyde (11.1 mL, 10C mmole) followed by pyrrolidine (9.1 mL, 109 mmole). The mixture was stirred at room temperature overnight, cooled to about 0°C and filtered. The solid was washed once with 50 mL of ice-cold methanol and then dried in vacuo; 35.2 g. (75% yield) of the title product of this Example 1D was recovered. M.P. 133-135°C ¹H NMR (300 MHz, CDCl₃): 8.11 (1H, d, J=8.7Hz), 7.91 (1H, bs), 7.40-7.51 (2H, m), 7.24-7.38 (3H. m), 6.97 (1H, dd, J=8.7Hz, 2.4Hz), 6.91 (1H, d, J=2.4Hz), 5.40 (1H, bs).

E. 7-[(5-Fluoro-(2-(4,4-dimethyl-2-oxazolinyl)phenyl]-3-phenylmethylene-1-benzopyran-4-one

[0055] To a stirred solution of 2-(4-fluorophenyl)-4,4-dimethyl-2-oxazoline (1.0 eq in tetrahydrofuran, 0.5 M concentration) at about -78°C under N₂ was added n-butyllithium in hexanes (1.1 eq., 2.5 M solution). The mixture was stirred at about -78°C for about 1 hour, then ZnCl₂ (1M solution in ether, 1.1 eq.) was added. The mixture was warmed to about 10°C over about 1 hour to give 2-(4-fluorophenyl-2-chlorozinc)-4,4-diethyl-2-oxazoline (not isolated). To this solution was added 7[((trifluoromethyl)sufonyl)oxy]-3-phenylmethylene-1 -benzopyran-4-one (1.0 eq.) and Pd(PPh₃)₄ (0.02 eq.). The mixture was refluxed (about 68°C) for about 3 hours, cooled to room temperature and poured into NH₄Cl solution. The solution was extracted 3 times with diethyl ether and the combined organic fraction dried over MgSO₄. Filtration followed by solvent removal in vacuo and column chromatography (silica gel - 2:1 hexane:ether) gave the title compound of this Example 1F as a yellow solid, 65% yield, m.p. 110-112°C. ¹H-NMR (300 MHz, CDCl₃):8.04 (1H, d), 7.91(1H, s), 7.78 (1H, dd), 7.41-7.52 (3H, m), 7.31 (2H, d), 7.06-7.18 (3H, m), 7.02 (1H, s), 5.40 (2H, s), 3.86 (2H, s), 1.31 (6H, s).

F. (3S*,4R*)-7-[5-Fluoro-(2-(4,4-dimethyl-2-oxazolinyl)phenyl]4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0056] To a stirred solution of the compound from Example 1 E in THF (0.1 1M) at about 0°C was added LiAlH₄ (1M in ether, 2.2 eq) dropwise over about 10 minutes. The mixture was warmed to room temperature and stirred for about 12 hours. The mixture was cooled to about 0°C, quenched with Rochelles salt, and filtered through diatomaceous earth. The aqueous layer was extracted twice with ethyl acetate, and the combined organic layers were washed with brine and dried over MgSO₄ Filtration and solvent removal afforded a yellow oil. Chromatography over silica gel (ethyl acetate:hexane) afforded a 60% yield of a white solid. M.P. 65-70°C (decomposed). Anal. calcd. for C₂₇H₂₆NO₃F. C, 75.15; H, 6.07; N, 3.25. Found: C, 74.75, H, 6.02, N. 3 09. ¹H-NMR (300 MHz, CDCl₃): 7.70 (1H, dd), 7.02-7.37 (8 H. m), 6.96 (1H, dd), 7.91 (1H, d), 4.51 (1H, d), 4.23 (1H, dd), 4.39 (1H, dd), 3.87 (2 H, dd), 2.74 (1H, dd), 2.55 (1H, dd), 2.18-2.28 (1H, m). 1.31 (6H, d).

G. (3S*,4R*)7-(2-Carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0057] The compound from step 1F is dissolved in methyl iodide (0.5M) at room temperature and stirred for about 24 hours. The methyl iodide was removed in vacuo, the oily solid was dissolved in CH₂Cl₂ and the solvent removed in vacuo. This operation was repeated to remove traces of methyl iodide. The solid was dissolved in methanol (0.5M) and 2M NaOH (0.5M) was added and the mixture was refluxed for about 5 hours, cooled to room temperature and acidified to pH 2 with 1 M HCI. The mixture was extracted twice with ethyl acetate, washed with brine, and dried over MgSO₄. Filtration and solvent removal in vacuo, followed by chromatography (silica gel, 10:1 methylene chloride:methanol) gave the desired acid, 93% yield. ¹H-NMR (300 MHz, CD₃COCD₃): 7.80 (1H, dd), 7.48 (1H, d), 7.18 (7H, m), 7.13 (1H, dd) 6.91 (1H, dd), 6.80 (1H, d), 4.52 (1H, d), 4.23 (1H, dd), 3.96 (1H, dd), 2.89 (1H, dd), 2.54 (1H, dd), 2.19-2.30 (1H, m).

H1. (3S,4R)-7-(2-Carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0058] The compound from step 1G is dissolved in diethyl ether (0.1M) and warmed to reflux. To the solution was added dropwie S(-)methylbenzylamine (1 eq) in diethyl ether (0.1M), dropwise over about 10 minutes. The mixture was cooled to room temperature and stirred for about 48 hours. The precipitated salt was filtered then stirred again at reflux in diethyl ether (0.1M) for about 24 hours, followed by filtration. The salt (M.P. = 170-173°C) was taken up in methylene chloride and washed 3 times with 1M HCI, then once with bnne, dried over MgSO₄, and filtered. Solvent removal in vacuo and recrystallization (1:1-hexane:ether) gave fine white crystals, more than 99.8% enantiomeric excess by HPLC analysis [a]_D²⁵=+23.8, c=0.6 in CHCl₃. M.P. = 119-121°C Anal. Calcd. for C₂₃H₁₉O₄F: C, 73.01; H, 5.06. Found: C, 72.88; H, 4.76.

H2. (3R,4S)7-(2-Carboxy-5-fluorophenyl)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0059] The filtrate from the combined salt slurries in Example 1D was washed three times with 1M HCI, once with brine, and dried over MgSO₄. Filtration and solvent removal gave a yellow solid. A similar procedure as described in Example 1 D using R (+) methylbenzyl amine afforded the desired product [a]_D²⁵=-23.4 (c=0.6 in CHCl₃), M.P. = 118-120°C. Anal. Calcd. for C₂₃H₁₉O₄F: C, 73.01. H, 5.06 Found: C, 73.03; H, 4.84.

I 3S,4R)-7-(2-Carbobenzyloxyamino-5-fluoro)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0060] To a solution of the compound prepared in Example 1H1 (1 mmole) in 10 mL of 1,4-dioxane was adced 1.05 eq of diphenylphosphrylazide, 1.1 eq of benzyl alcohol and 2 2 eq of triethylamine. The mixture was refluxed for about 16 hours, the solvent removed under vacuum and the residue chromatographed over silica gel (1:1-hexane: EtOAc) to afford the N-CBZ product (68% yield) ¹H-NMR (300 MHz, CDCl₃): 8.10 (1H, bs), 7.48-7.28 (11H, m), 7.05 (1H, dt, J=7.1, 2.0 Hz), 6.97-6.83 (3H, m), 6.67 (1H, s), 5.17 (2H, s), 4.56 (1H, s), 4.27 (1H, dd, J=13.1, 1.8 Hz). 4.01 (1H. dd, J=13.2, 5.0 Hz), 2.80 (1H, dd, J=14.2, 7.0 Hz), 2.58 (1H, dd, J=14.2, 9.1 Hz), 2.40-2.22 (1H, m).

J. (3S,4R)-7-(2-Trifluoromethanesulfonylamine-5-fluoro)-4-hydroxy-3-phenylmethyl-2H-1-benzopyran

[0061] To a solution of the compound prepared in Example 1l in 10 mL of EtOH was added 0.05 eq by weight of Pd(OH₂) and the slurry was hydrogenated on a Parr® shaker apparatus at 1 Atm. for about 3 hours. The mixture was filtered through Celite® and the filtrate evaporated. The yellow oil was redissolved in CH₂Cl₂ (10 mL), cooled to about 0°C and triethylamine (2.2 eq) added, followed by trifluoromethanesulfonic anhydnde (1.1 eq). After stirring for about 2 hours, 2 eq of solid NaOMe was added, the reaction stirred for about 15 minutes, and H₂O added (10 mL). The mixture was adjusted to pH with 0.1M HCI then extracted with 3x10 mL EtOAc. The combined organic layers were washed with brine, dried over MgSO₄, filtered and solvent remove under vacuum to afford a yellow semisolid. Chromatography over silica gel (1:1-10:1 EtOAc-Hexane) gave the desired sulfonamide. M.P.: 63-65°C.

Claims

1. A method for suppressing the rejection of allogeneic transplants in a mammal, including a human. comprising administering to said mammal an effective amount of a compound of the formula

or a pharmaceutically acceptable acid addition salt thereof; wherein

n is 1,2 or 3:

A is oxygen, sulfur, CH₂, NH or N(C₁-C₆)alkyl;

B is CHR³ wherein each R³ is hydrogen, (C₆-C₁₀)aryl(C₆-C₁₀)aryl or (C₆-C₁₀)aryl(C₆-C₁₀)aryl(C₆-C₁₀)alkyl.

R¹ is tetrazolyl, carboxy, carboxy(C₂-C₆)alkenyl optionally substituted by one or two (C₁-C₆)alkyl groups; (C₁-C₆)alkyl, (C₃-C₇)cycloalkyl, (C₆-C₇)cycloalkyl(C₁-C₆)alkyl wherein the alkyl or cycloalkyl groups are optionally substituted by hydroxy, carboxy or tetrazolyl; or a group of the formula

wherein

a is 0, 1, 2, 3 or 4;

R⁸ and R⁹ are each independently hydrogen or (C₁-C₆)alkyl; and

R¹⁰ and R¹¹ are each independently hydrogen, hydroxy, (C₁-C₆)alkyl, perfluoro(C₁-C₆)alkyl, (C₁-C₆)alkylsulfinyl, (C₆-C₁₀)arylsulfinyl, R¹⁵sulfonyl wherein R¹⁵ is (C₁-C₆)alkyl, perfluoro(C₁-C₆)alkyl, (C₃-C₈)cycloalkyl, (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl; or (C₆-C₁₀)aryl wherein each aryl or heteroaryl substituent is optionally substituted by one or two groups selected from fluoro, chloro, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl and (C₆-C₁₀)arylsulfonyl;

or a group of the formula

wherein

b is 0, 1, 2 or 3;

c is 0 or 1

Y is oxygen, sulfur, CH₂, NH or N(C₁-C₆)alkyl: and

Z is (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl wherein the aryl or heteroaryl substituents are optionally substituted by one to three groups selected from fluoro, chloro, (C₁-C₆)alkyl optionally substituted by hydroxy; R¹²SO₂NH wherein R¹² is (C₁-C₆)alkyl or perfluoro(C₁-C₆)alkyl; R¹³SO₂NHCO wherein R¹³ is (C₁-C₆)alkyl. (C₆-C₁₀)aryl or (C₄-C₉)heteroaryl wherein aryl or heteroaryl substituents are optionally substituted by R¹⁴, (C₆-C₁₀)aryl or R¹⁴(C₆-C₁₀)aryl wherein R¹⁴ is as defined above; (R¹⁵SO₂)NH, (R¹⁵CO)NH, (R¹⁵CO₂)NH wherein R¹⁵ is as defined above; (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₁-C₆)alkylsulfonyl, carboxy, tetrazolyl or the group of formula II wherein a, R⁸, R⁹, R¹⁰ and R¹¹ are as defined above; and

R² is hydrogen, fluoro, chloro, (C₁-C₆)alkyl, (C₁-C₆)alkoxy, perfluoro(C₁-C₆)alkyl, perfluoro(C₁-C₆)alkoxy, (C₁-C₆)alkylthio, (C₁-C₆)alkylsulfinyl, (C₆-C₁₀)arylsulfinyl, (C₁-C₆)alkylsulfonyl or (C₆-C₁₀)arylsulfonyl.

2. A method according to claim 1, wherein the compound that is administered is one wherein n is 2.

3. A method according to claim 1, wherein the compound that is administered is one wherein A is oxygen.

4. A method according to claim 1, wherein the compound that is administered is one wherein n is 2 and B is in the 3- position.

5. A method according to claim 1, wherein the compound that is administered is one wherein R² is hydrogen or fluoro.

6. A method according to claim 1, wherein the compound that is administered is one wherein n is 2 and R¹, in the 7-position, is 2-carboxyphenyl, 2-carboxy-5-chlorophenyl, 2-carboxy-4-chlorophenyl, 2-carboxy-3-fluorophenyl, , 2-carboxy-5-fluorophenyl, 2-carboxy-5-chlorophenyl, 2-carboxy-5-trifluoromethylphenyl, 2-trifluoromethylsulfonylamine-5-fluorophenyl, 2-carboxy-4-fluorophenyl, 2-carboxy-6-fluorophenyl, 2-tetrazoyl-5-fluorophenyl or 3-carboxyphenyl.

7. A method according to claim 1, wherein the compound that is administered is one wherein n is 2; A is oxygen; B is in the 3- position; R² is hydrogen or fluoro; and R¹, in the 7-position, is 2-carboxyphenyl, 2-carboxy-5-chlorophenyl, 2-carbox-4-chlorophenyl, 2-carboxy-3-fluorophenyl, 2-carboxy-5-fluorophenyl, 2-carboxy-5-trifluoromethylphenyl, 2-trifluoromethylsulfonylamine-5-fluorophenyl, 2-carboxy-4-fluorophenyl, 2-carboxy-6-fluorophenyl, 2-tetrazoyl-5-fluorophenyl or 3-carboxyphenyl.